Efficient photodetectors and photovoltaic cells from composites of fullerenes and conjugated polymers: photoinduced electron transfer

Polymer-based photodetectors and photovoltaic cells have been made by using conjugated polymer (MEH-PPV) as donor and C60 as acceptor. Optical quality composite films are spin cast from 1,2-dichlorobenzene (ODCB) solution. The light intensity and composition dependences of device characteristics have been studied. By optimizing the donor-acceptor ratio, a power conversion efficiency of 2.5% and a collection efficiency of 26% have been achieved for photovoltaic cells. Under reverse bias, a photosensitivity of approximately 0.26A/W has been achieved at 430 nm. The excellent photoresponse is attributed to efficient charge separation and collection by the donor-acceptor heterojunctions in the bulk of the composite films.